A radio network node, a wireless device and methods therein for resuming a radio connection

Abstract

A UE and a method for resuming a radio connection in a communications network comprising a first RAT and a different second RAT. The UE operates in a first cell served by the first RAT. When a connection with the first cell is suspended, the UE performs a re-selection to a second cell served by the second RAT, and triggers RRC resume in the second cell. The UE receives a first set of parameters associated with the first cell, which first set comprises at least one parameter identifying the UE or the first cell. Further, the UE receives a second set of parameters associated with the second cell, which second set comprises at least one parameter identifying the UE or the second cell. The UE determines a security token based on the first and second sets, and transmits the security token to the second cell.

1 . A method performed by a wireless device for resuming a radio connection in a wireless communications network comprising a first Radio Access Technology, RAT, and a second RAT being different from the first RAT, wherein the wireless device is operating in a first cell served by a first radio network node operating in the first RAT, and wherein the method comprises:
 when a connection with first cell is suspended,
 performing a re-selection to a second cell served by a second radio network node operating in the second RAT; 
 triggering an RRC resume procedure in the second cell; 
 receiving a first set of parameters associated with the first cell, wherein the first set of parameters comprises at least one parameter identifying the wireless device or the first cell; 
 receiving a second set of parameters associated with the second cell, wherein the second set of parameters comprises at least one parameter identifying the wireless device or the second cell; 
 determining an updated version of one or more parameters of the first set of parameters or an updated version of one or more parameters of the second set of parameters; 
 determining a security token based on at least one out of the first set of parameters and the updated version of the one or more parameters of the first set of parameters, and based on at least one out of the second set of parameters and the updated version of the one or more parameters of the second set of parameters; and 
 transmitting to the second cell, a resume request message comprising the security token. 
   
     
     
         2 . The method of  claim 1 , wherein the first set of parameters comprises one or more out of: a Cell Radio Network Temporary Identifier, C-RNTI, Inactive Radio Network Temporary Identifier, I-RNTI, identifying the wireless device, and a Physical Cell Identifier, PCI, identifying the first cell, and wherein the second set of parameters comprises a Cell ID or a PCI identifying the second cell. 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein the determining of the updated version of the one or more parameters of the first set of parameters comprises:
 converting the one or more parameters of the first set of parameters to a format corresponding to the format of the one or more parameters of the second RAT by performing one or more out of:
 mapping, recalculating, or truncating the one or more parameters of the first set of parameters to a shortened bit string when the first RAT is 5G New Radio, NR, technology and the second RAT is Long Term Evolution, LTE, technology, and 
 mapping, recalculating, or padding the one or more parameters of the first set of parameters to an extended bit string when the first RAT is LTE and the second RAT is NR, and 
   using the converted one or more parameters of the first set of parameters in one or more variables defined in the second RAT as input in calculation of the security token for the second RAT.   
     
     
         5 . The method of  claim 4 , wherein the determining of the updated version of the one or more parameters of the second set of parameters comprises:
 converting the one or more parameters of the second set of parameters to a format corresponding to the format of the one or more parameters of the first set of parameters by performing one or more out of:
 mapping, recalculating, or truncating the one or more parameters of the second set of parameters to a shortened bit string when the first RAT is LTE technology and the second RAT is NR technology and 
 mapping, recalculating, or padding the one or more parameters of the second set of parameters to an extended bit string when the first RAT is NR and the second RAT is LTE, and 
   using the converted one or more parameters of the second set of parameters in one or more variables defined in the first RAT as input in calculation of the security token for the first RAT.   
     
     
         6 . The method of  claim 1 , further comprising:
 creating a new variable comprising the one or more parameters of the first set of parameters in the format of the first RAT and comprising the one or more parameters of the second set of parameters in the format of the second RAT, and   wherein the determining of the security token comprises:   using the new variable as input in calculation of the security token for the second RAT.   
     
     
         7 . The method of  claim 6 , wherein the new variable is an extension of an existing variable. 
     
     
         8 . The method of  claim 1 , wherein the determining of the updated version of the one or more parameters of the first set of parameters or the updated version of the one or more parameters of the second set of parameters comprises:
 extending definition of existing variables to use one or more values in the second RAT format in place of the one or more parameters of the first set of parameters.   
     
     
         9 . The method of  claim 1 , wherein the determining of the updated version of the one or more parameters of the first set of parameters or the updated version of the one or more parameters of the second set of parameters comprises:
 receiving, from the first radio network node or the second radio network node, an instruction how to convert the one or more parameters of the first set of parameters into a format corresponding to the format of the one or more parameters of the second set of parameters or how to convert the one or more parameters of the second set of parameters into a format corresponding to the format of the one or more parameters of the first set of parameters.   
     
     
         10 . A method performed by a first radio network node for assisting a wireless device in resuming a radio connection in a wireless communications network comprising a first Radio Access Technology, RAT, and a second RAT being different from the first RAT, wherein the wireless device is operating in a first cell served by the first radio network node operating in the first RAT, and wherein the method comprises:
 providing the wireless device with a first set of parameters associated with the first cell, wherein the first set of parameters comprises at least one parameter identifying the wireless device or the first cell, and when a connection between the wireless device and the first cell is suspended:   receiving, from a second radio network node operating in the second RAT, a second set of parameters associated with a second cell served by the second radio network node;   receiving, from the second radio network node, a security token received by the second radio network node in a resume request message from the wireless device when a radio connection with the first radio network node has been suspended;   determining an updated version of one or more parameters of the first set of parameters or an updated version of one or more parameters of the second set of parameters and determining an expected security token based on at least one out of the first set of parameters and the updated version of the one or more parameters of the first set of parameters, and based on at least one out of the second set of parameters and the updated version of the one or more parameters of the second set of parameters; and   by means of the received security token and the determined expected security token, verifying the wireless device's identity;   when the wireless device is verified as valid, transmitting, to the second radio network node, one or more configurations and/or parameters relating to the radio connection to be resumed.   
     
     
         11 . (canceled) 
     
     
         12 . The method of  claim 10 , wherein the determining of the updated version of the one or more parameters of the first set of parameters comprises:
 converting the one or more parameters of the first set of parameters to a format corresponding to the format of the one or more parameters of the second RAT by performing one or more out of:
 mapping, recalculating or truncating the one or more parameters of the first set of parameters to a shortened bit string when the first RAT is 5G New Radio, NR, technology and the second RAT is Long Term Evolution, LTE, technology, and 
 mapping, recalculating, or padding the one or more parameters of the first set of parameters to an extended bit string when the first RAT is LTE and the second RAT is NR; and 
   wherein the determining of the security token comprises:
 using the converted one or more parameters of the first set of parameters in one or more variables defined in the second RAT as input in calculation of the security token for the second RAT. 
   
     
     
         13 . The method of  claim 12 , wherein the determining of the updated version of the one or more parameters of the second set of parameters comprises:
 converting the one or more parameters of the second set of parameters to a format corresponding to the format of the one or more parameters of the first set of parameters by performing one or more out of:
 mapping, recalculating or truncating the one or more parameters of the second set of parameters to a shortened bit string when the first RAT is LTE technology and the second RAT is NR technology, and 
 mapping, recalculating, or padding the one or more parameters of the second set of parameters to an extended bit string when the first RAT is NR and the second RAT is LTE; and 
   wherein the determining of the security token comprises:
 using the converted one or more parameters of the second set of parameters in one or more variables defined in the first RAT as input in calculation of the security token for the first RAT. 
   
     
     
         14 . The method of  claim 10 , further comprising:
 creating a new variable comprising the one or more parameters of the first set of parameters in the format of the first RAT and comprising the one or more parameters of the second set of parameters in the format of the second RAT, and wherein the determining of the security token comprises:   using the new variable as input in calculation of the security token for the second RAT.   
     
     
         15 . The method of  claim 14 , wherein the new variable is an extension of an existing variable. 
     
     
         16 . The method of  claim 10 , wherein the determining of the updated version of the one or more parameters of the first set of parameters or the updated version of the one or more parameters of the second set of parameters comprises:
 extending definition of existing variables to use one or more values in the second RAT format in place of the one or more parameters of the first set of parameters.   
     
     
         17 . The method of  claim 10 , further comprising:
 providing the wireless device with an instruction how to convert one or more parameters of a first set of parameters associated with the first cell into a format corresponding to the format of the one or more parameters of the second set of parameters or how to convert the one or more parameters of the second set of parameters into a format corresponding to the format of the one or more parameters of the first set of parameters.   
     
     
         18 . A wireless device for resuming a radio connection in a wireless communications network comprising a first Radio Access Technology, RAT, and a second RAT being different from the first RAT, wherein the wireless device is configured to operate in a first cell served by a first radio network node configured to operate in the first RAT, and wherein the method comprises:
 when a connection with the first cell is suspended, the wireless device is configured to:
 perform a re-selection to a second cell served by a second radio network node operating in the second RAT; 
 trigger an RRC resume procedure in the second cell; 
 receive a first set of parameters associated with the first cell, wherein the first set of parameters comprises at least one parameter identifying the wireless device or the first cell; 
 receive a second set of parameters associated with the second cell, wherein the second set of parameters comprises at least one parameter identifying the wireless device or the second cell; 
 determine an updated version of one or more parameters of the first set of parameters or an updated version of one or more parameters of the second set of parameters; 
 determine a security token based on at least one out of the first set of parameters and the updated version of the one or more parameters of the first set of parameters, and based on at least one out of the second set of parameters and the updated version of the one or more parameters of the second set of parameters; and 
 transmit, to the second cell, a resume request message comprising the security token. 
   
     
     
         19 . The wireless device of  claim 18 , wherein the first set of parameters comprises one or more out of: a Cell Radio Network Temporary Identifier, C-RNTI, Inactive Radio Network Temporary Identifier, I-RNTI, identifying the wireless device, and a Physical Cell Identifier, PCI, identifying the first cell, and wherein the second set of parameters comprises a Cell ID or a PCI identifying the second cell. 
     
     
         20 . (canceled) 
     
     
         21 . The wireless device of  claim 18 , wherein the wireless device is configured to determine the updated version of the one or more parameters of the first set of parameters by converting the one or more parameters of the first set of parameters to a format corresponding to the format of the one or more parameters of the second RAT by performing one or more out of:
 mapping, recalculating or truncating the one or more parameters of the first set of parameters to a shortened bit string when the first RAT is 5G New Radio, NR, technology and the second RAT is Long Term Evolution, LTE, technology; and   mapping, recalculating or padding the one or more parameters of the first set of parameters to an extended bit string when the first RAT is LTE and the second RAT is NR; and   wherein the wireless device is configured to use the converted one or more parameters of the first set of parameters in one or more variables defined in the second RAT as input in calculation of the security token for the second RAT.   
     
     
         22 . The wireless device of  claim 21 , wherein the wireless device is configured to determine the updated version of the one or more parameters of the second set of parameters by converting the one or more parameters of the second set of parameters to a format corresponding to the format of the one or more parameters of the first set of parameters by performing one or more out of:
 mapping, recalculating or truncating the one or more parameters of the second set of parameters to a shortened bit string when the first RAT is LTE technology and the second RAT is NR technology, and   mapping, recalculating or padding the one or more parameters of the second set of parameters to an extended bit string when the first RAT is NR and the second RAT is LTE; and   wherein the wireless device is configured to use the converted one or more parameters of the second set of parameters in one or more variables defined in the first RAT as input in calculation of the security token for the first RAT.   
     
     
         23 - 26 . (canceled) 
     
     
         27 . A first radio network node for assisting a wireless device in resuming a radio connection in a wireless communications network comprising a first Radio Access Technology, RAT, and a second RAT being different from the first RAT, wherein the wireless device is configured to operate in a first cell served by the first radio network node configured to operate in the first RAT, and wherein the first radio network node is configured to:
 provide the wireless device with a first set of parameters associated with the first cell, wherein the first set of parameters comprises at least one parameter identifying the wireless device or the first cell, and when a connection between the wireless device and the first cell is suspended:   receive, from a second radio network node operating in the second RAT, a second set of parameters associated with a second cell served by the second radio network node;   receive, from the second radio network node, a security token received by the second radio network node in a resume request message from the wireless device when a radio connection with the first radio network node has been suspended;   determine an updated version of one or more parameters of the first set of parameters or an updated version of one or more parameters of the second set of parameters;   determine an expected security token based on and at least one out of the first set of parameters and the updated version of the one or more parameters of the first set of parameters, and based on at least one out of the second set of parameters and the updated version of the one or more parameters of the second set of parameters; and   by means of the received security token and the determined expected security token, verify the wireless device's identity;   when the wireless device is verified as valid, transmit, to the second radio network node, one or more configurations and/or parameters relating to the radio connection to be resumed.   
     
     
         28 - 36 . (canceled)